Department of Defense
High Performance Computing Modernization Program

Enabling IPv6

The following guide explains the steps involved in enabling Internet Protocol version 6 (IPv6) on IBM AIX systems for external communications. You must be running AIX5L or higher. For internal node-to-node communications via IPv6, you must be running AIX7.1 or higher.

The basic process is as follows:

1. Run the autoconf6 command. This brings up IPv6 capable interfaces. Do this by executing either:

/usr/sbin/autoconf6 -i interfacename # Bring up a specific interface, such as en0


/usr/sbin/autoconf6 "" -a # Bring up all IPv6 capable interfaces

2. Start the ndpd-host service. This starts the neighbor discovery protocol daemon. Do this by executing:

/usr/sbin/startsrc -s ndpd-host

To configure IPv6 at system startup, put the above entries in the /etc/rc.tcpip file as follows:

start /usr/sbin/autoconf6 “” -a

start /usr/sbin/ndpd-host “$src_running”

This procedure has been tested with AIX5L version 5.1. It should work with later versions as well.


IPv6 Concepts and Applicability on AIX

IPv6 Configuration and Introduction

The AIX autoconf6 and ndpd-host man pages. 


Disabling IPv6

The basic process is as follows:

1. Edit the /etc/rc.tcpip file and comment out the lines that start the autoconf6 and ndpd-hosts processes:

# start /usr/sbin/autoconf6 …options
# start /usr/sbin/ndpd-host …options

3. Reboot

4. Open a command shell and enter the following:

lsattr -El lo0
chdev -l lo0 -a netaddr6=''"
ifconfig lo0 inet6 ::1/0 delete
ifconfig –a

5. IPv6 addresses may still appear in the

ifconfig –a output

for some network interface(s) or additional static IPv6 routes may still be shown for inet0. If so, delete the associated IPv6 addresses.

6. Reboot.